1. Field of the Invention
The present invention relates to a test apparatus that tests an electronic device such as a semiconductor circuit.
2. Related Art
Conventionally, a test apparatus for testing an electronic device has had a configuration including a mainframe that is the test apparatus main body, a socket board that mounts thereon the electronic device, and a test head that holds the socket board. The mainframe generates test patterns and source power to be supplied to the electronic device, and supplies them to the test head via cables.
Moreover, a power supply line of the socket board for transmitting source power to the electronic device has a bypass capacitor hi the vicinity of the electronic device. The provision of the bypass capacitor can reduce noises in the power supply line and follow fluctuation of power supply currents at high speed.
As an example of a test for the electronic device, there is also known a test for measuring power supply currents of the electronic device. When performing such a test, it is difficult to measure the power supply currents with high precision due to leakage currents of the bypass capacitor. For this reason, the socket board has a relay that switches whether the bypass capacitor and the power supply line is connected or not.
However, there is developed a more undersized socket board in terms of uniformity of temperature distribution or machine precision in connection with the test head. Moreover, in order to improve test efficiency, the number of electronic devices simultaneously examined increases and thus the number of electronic devices mounted on the socket board increases. For this reason, it becomes difficult to guarantee a region mounting the bypass capacitor and the relay.
Moreover, wires for controlling a relay and wires for use in a relay driving power supply become necessary when providing the bypass capacitor and the relay in the socket board. For this reason, since an area of the socket board should be increased, it is difficult to be compatible with the above-described miniaturization.
For example, when providing the bypass capacitor and the relay in the test head, the area of the socket board can be reduced. However, since noises or the like generated from power supply lines between the test head and the electronic device cannot be removed, the electronic device cannot be tested with high precision.